bug#11169: 24.0.95; (Wish/FR): Revert an archive member

[Stefan Monnier]

> It would be quite useful if there is a way to revert an archive
> member.  It could work something like this:
> 1. Revert a buffer
> 2. Check if the buffer is from an archive (See `archive-superior-buffer')
> 3. Check if the parent archive has changed and revert the parent archive
> 4. Refresh this and possibly other open archive members

A first step would be to make it work in the following case:
1- the user does M-x revert-buffer in the archive buffer.
2- the user does M-x revert-buffer in the archive member buffer.

One way to get this result (not necessarily the simplest, but one that
would make a lot of sense in general) is to extend archive-mode with
a file-name-handler.
E.g. if you open a /foo/bar.zip, you could access its members with C-x
C-f /foo/bar.zip#/toto.c.


        Stefan